This invention pertains to motors.
More particularly, the invention pertains to concentric, multiple pole, shaded pole, subfractional-horsepower induction motors.
In another respect, this invention relates to a sleeve for a bearing and to a method of making the sleeve.
In a further more particular respect, the invention relates to a sleeve for a cylindrical bearing which permits the bearing to be loaded into the sleeve and turned to a position in which the bearing is retained in the sleeve.
In still another respect, the invention relates to a method of manufacture of a sleeve for an arcuate bearing when the bearing has an outer diameter less than about one inch and a height less than the outer diameter of the bearing.
Subfractional-horsepower induction motors have a horse-power (HP) of {fraction (1/20)} HP or less, typically {fraction (1/150)} HP to {fraction (1/20)} HP. Such motors ordinarily include a single piece stator, an armature rotationally mounted in an opening in the stator, two or more primary poles, and two or more xe2x80x9cshadedxe2x80x9d or secondary poles. A shaded pole or coil is a piece of material than can conduct electricity to create another magnetic field inside the primary magnetic field generated in the motor. The primary magnetic field is generated by wire wrapped around a primary pole. The secondary pole or magnetic field gives the motor its initial direction and rotation when it starts. The secondary pole makes the motor spin by changing the characteristics of the magnetic field in the stator. Subfractional-horsepower motors are used to power water pumps in evaporative coolers and are used in other applications which require a small motor. The design and efficiency of subfractional horsepower induction motors have in large part remained unchanged for many years.
Arcuately shaped bearings and sleeves which house such bearings are known in the art.
One prior art bearing and its associated sleeve or housing are disclosed in the article xe2x80x9cComposite Spherical Bearing Is Self-Aligningxe2x80x9d which appears at page 102 of the Apr. 4, 1993 Design News magazine. The bearing is spherically shaped, includes a pair of ends or flats and includes an outer spherical convex surface which extends between the ends. A cylindrical aperture is formed through the bearing. The cylindrical aperture includes a centerline. The outer spherical surface of the bearing symmetrically circumscribes the cylindrical aperture and also symmetrically circumscribes and is spaced apart from the centerline of the cylindrical aperture. In sum, the appearance of the spherically shaped bearing is akin to that of a bead on a necklace, where the bead is not completely spherical but has been truncated to form two parallel, spaced apart opposed ends or flats. The spherically shaped bearing is positioned in its associated sleeve by (1) inserting the bearing through a slot formed in the race in an orientation in which the flats or ends of the bearing are parallel to the sides of the slot, and (2) rotating the bearing inside the sleeve to a position in which sleeve securely retains the bearing during use. The sleeve includes an inner spherical or concave surface which conforms to and mates with the outer spherical surface of the bearing such that the bearing can rotate and turn in the sleeve. In many cases, the inner concave surface of the sleeve can be produced utilizing an expanding mandrel. When, however, the diameter of the bearing, and consequently of the opening in the sleeve, becomes less than about one inch, utilizing an expanding mandrel machine tool becomes impractical because the mandrel, due to the thinness of the fingers comprising the mandrel, will not last for many cycles and typically may only last a few hundred cycles before failing and requiring the providing of a brand new expanding mandrel.
Accordingly, it would be highly desirable to provide an improved subfractional-horsepower induction motor and method for producing the same.
It would also be highly desirable to provide an improved sleeve with an inner concave surface shaped to house a small bearing with an outer convex surface and to provide a practical, economical manufacturing method and apparatus for producing such a sleeve so that thousands or millions of sleeves can be reliably manufactured with a single set of manufacturing apparatus.
Therefore, it is a principal object of the invention to provide an improved subfractional-horsepower induction motor and method for producing the same.
A further object of the invention is to provide an improved subfractional-horsepower induction motor which permits the mounting of wound wire on the stator before the final assembly of the stator.
Another object of the invention is to provide an improved concentric subfractional-horsepower induction motor which utilizes an armature or rotor which can be interchangeably utilized on a C-frame stator in a subfractional-horsepower induction motor.
Still a further object of the invention is to provide an improved concentric subfractional-horsepower induction motor which utilizes reluctance gaps to force the primary magnetic field into the rotor or armature of the motor to increase the strength of the motor.
Yet another object of the invention is to provide an improved mounting bracket for a subfractional-horsepower induction motor.
Yet still another object of the invention to provide an improved sleeve for a bearing having a concave outer surface.
A further object of the invention is to provide an improved method and apparatus for producing a sleeve for a bearing.
Another object of the invention is to provide an improved method and apparatus for producing a sleeve for a small bearing having a diameter of about one inch or less.